(1) Field of the Invention
The invention relates to an apparatus and method for cutting and harvesting infestations of bottom growing aquatic vegetation in shallow areas of water bodies.
(2) Description of the Prior Art
Bottom growing nuisance aquatic plants degrade waters for swimming, boating, fishing, aesthetic and health aspects by lake users and waterfront property owners. Currently these plants can be removed by physical, mechanical, chemical and biological methods each with significant drawbacks.
Physical methods, such as barriers disturb water-bottom ecology and often result in gassing of decomposing plant like vegetation under the barrier. Examples of such mat material are filtration mats, discarded rugs and thin sheets of metal plate.
Mechanical bottom cutting and drag devices such as commonly used rake like tools and typical garden type cultivators that have transverse bars, tines and handles stir up bottom sediments which release nutrients back into the waters and disturb water bottom ecology. These nutrients enhance further aquatic plant growth and digging up the bottom sediments can have a negative impact on the lake bottom ecology.
The following patents are examples of bottom, metal, drag-type cutters which dig up bottom sediment as well as not integrally harvesting the floating cut aquatic plants. These floating plants can then reestablish themselves in other areas of the water body. A further disadvantage of these water bottom drag-type cutters is that they are prone to be blocked or other wise interfered with during cutting by rocks, logs and debris that have accumulated on the lake bottom. U.S. Pat. No. 6,250,054 Kramer; U.S. Pat. No. 2,065,733 Pearson; U.S. Pat. No. 2,702,975 Friesen; U.S. Pat. No. 2,790,297 Gardner; U.S. Pat. No. 3,601,956 Akermanis; U.S. Pat. No. 3,601,956; U.S. Pat. No. 4,137,693 Thompson et al; U.S. Pat. No. 4,375,299 Laven; U.S. Pat. No. 3,863,237 Doer; U.S. Pat. No. 4,696,149 Hawk; U.S. Pat. No. 4,852,337 Peterson; U.S. Pat. No. 5,189,867 Schmidt; and U.S. Pat. No. 5,493,850 Torkelson; each show methods for cutting plants using a drag bar with a cutting edge. U.S. Pat. No. 4,999,982 Kriger describes the use of a dragging bar grate for cutting aquatic plants. U.S. Pat. No. 4,583,353 Shaver shows a triangular drag bar for cutting plants.
Chemical and biological methods are under investigation. However, there is concern about these methods, because of questions of effectiveness, damage to water ecology, known and unknown water related human health impacts and possible liability considerations for the user.
Another type of plant cutting involves the commercial mechanical lake weed harvesters having reciprocating knives and conveyors. These machines are heavy, complicated, costly and hazardous. Further, these machines are unworkable in shallow areas of lakes and other bodies of water, because of hydraulic boat draft problems resulting in grounding of the harvester and engine cooling water problems from intake of lake bottom sediments into the engine. Examples of commercial powered and mechanized lake weed harvesters are U.S. Pat. No. 4,616,588 Caddick; U.S.Pat. No. 3,238,708 Zickeford; and U.S. Pat. No. 5,404,696 Vasby. These harvesting units are expensive, require considerable maintenance, need US Coast Guard permits in US navigable waters and require marine Workman""s Compensation insurance under the Jones Act.
There are also wheeled garden rakes that are used on dry land. Codding U.S. Pat. No. 4,945,996 and Foeller U.S. Pat. No. 5,287,935 are examples of such dry land garden rakes.
A principal object of the present invention is to provide an effective and very manufacturable at a reasonable cost apparatus and method for using the same for cutting and harvesting infestations of aquatic vegetation in shallow areas of water bodies, such as lakes.
A further object of the invention is to provide an improved, versatile, light-weight multifunctional harvesting device and method for bottom growing aquatic plants that minimizes the problems of the current practices and can be operated manually by one person in shallow waters.
A further object of the invention provides an economical, versatile, aquatic plant harvester with optional cutting method attachments that can be operated by one person in water body shallows to maintain a quality of water suitable for swimming, boating, fishing and other recreation uses and enjoyment.
A still further object of the present invention is to provide an improved multifunctional mobile harvesting device for lake bottom growing plants and methods that guide plant stems into a cutting device above the water body bottom in shallow areas, collects the cut aquatic plants for transport to onshore sites and eventual use in composting for garden and agricultural activities, that can be operated by one person with or without onshore power devices and that removes phosphorus contained in the cut vegetation from the water body.
These objects are accomplished by providing an improved harvesting apparatus that cuts aquatic plants at a predetermined distance above the lake or the like bottom using a planar horizontal deck with a plurality of closely spaced planar metal bars that efficiently guide the plant stems into confined spaces between the plurality of transverse bars until the stems become compacted within the spaces between the bars and eventually against the transverse stainless steel filaments positioned at a predetermined distance from the distal end of the metal deck bars where the steel filaments cut the wedged plant stems. The harvesting device with planar metal deck bars and transverse cutting filaments provide underwater cutting of the plant stems by movement of the harvester in either the forward or the reverse direction of motion with attachable cutting devices at both ends of the harvester.
A flexible plastic grid integral with the harvester collects the cut aquatic plants containing phosphorus and retains the plants until transported on the harvester to an onshore location for manual dumping by simple removal of the appropriate segments of the flexible plastic grid to the front or to the back of the harvester. The cut plants can then be dewatered, composted and the contained phosphorus used for garden or other agricultural purposes.
The harvester can be provided with wheels and air-filled tires for easy mobility and buoyancy adjustment that can be moved by one person across the bottom of the water body to minimize the disturbance of the lake bottom sediment ecology as well as passing over obstacles of rocks, logs and debris on the lake bottom.
The harvester can be operated by one person using a rigid handle that can move up or down vertically over a 180 degree arc for pulling or pushing the harvester apparatus in the forward or reverse direction as needed, with or without the use of onshore auxiliary power and that cuts aquatic plants moving in either direction. The accessory plant cutting attachments needed for variation in plant stem cutting characteristics can be attached, such as with bolts to either end of the harvester deck.
The harvester buoyancy is balanced by the apparatus""s weight and hydraulic buoyant forces by use of pneumatic tires on wheels and other floatation and/or weight addition devices added to the deck that optimizes wheel penetration into the bottom sediments thereby enhancing manual mobility of the harvester by one person in shallow waters. This also minimizes the disturbance of the water body bottom sediment ecology.